1. Field of the Invention
This invention pertains to electrodes for nerves. More particularly, this invention pertains to such electrodes and signals for placement on the vagus nerve.
2. Description of Related Art
In the prior art, treatments including application of an electrical signal directly to a nerve are known. Examples of such are shown in commonly assigned US Patent Application Publication No. US 2005/0038484 A1 published Feb. 17, 2005. That patent application teaches a number of different therapies which involve applying an electrical signal to a nerve.
An electrical signal applied to a nerve may be a stimulation signal selected to create neural impulses which propagate on the nerve. An electrical signal may also be a blocking signal selected to inhibit the propagation of neural impulses at the point of electrical signal application on the nerve. The '484 patent application publication describes a treatment for obesity (as well as treatments for other disorders) which includes applying a blocking signal to the nerve.
There are many different ways for applying a signal to a nerve. FIG. 7 of the '484 patent application publication shows an apparatus for applying a signal across the esophagus to a vagus nerve lying on outer exterior surface of the esophagus. In the '484 application, the apparatus of FIG. 7 is described in the preferred embodiment for applying a blocking signal to the vagus nerves to down-regulate pancreatic exocrine secretion to treat pancreatitis. FIG. 5 of the '484 application illustrates placement of a band around the esophagus with electrodes on the band overlying the anterior and posterior vagus nerves. As described in the '484 application, blocking signals can be applied to the electrodes to down-regulate vagal activity for the treatment of obesity.
The prior art contains numerous examples of electrodes for placement on nerves and treatments for applying electrical signals to such nerves. For example, U.S. Pat. No. 4,979,511 to Terry, Jr. dated Dec. 25, 1990 teaches an electrode on a helical silicone rubber coil for placement on a cervical vagus nerve for treatment of epilepsy. Also, U.S. Pat. No. 5,215,089 to Baker, Jr. issued Jun. 1, 1993 teaches an electrode for placement on a vagus and U.S. Pat. No. 5,251,634 to Weinberg issued Oct. 12, 1993 and U.S. Pat. No. 5,531,778 to Maschino et al. issued Jul. 2, 1996 and U.S. Pat. No. 6,600,956 to Maschino et al. issued Jul. 29, 2003 teach vagal electrodes.
Other techniques are known for applying signals directly to a nerve. These include patches placed over the nerve with electrodes on the patch positioned to overlie the nerves. In so-called cuff electrodes, a portion of a nerve is dissected to permit a cuff to completely or partially encircle the nerve. An additional optional electrode format is such as that shown in a product brochure called “ATROSTIM Phrenic Nerve Stimulator”, AtroTech Oy, P.O. Box 28, Fin-33721, Tampere, Finland (June 2004). The ATROSTIM nerve stimulator includes electrodes on opposite sides of PTFE strips for placement on opposite sides of a phrenic nerve for quad-polar stimulation. Another phrenic nerve electrode is sold by Avery Laboratories, Inc., 61 Mall Drive, Commack, N.Y., USA. The Avery electrode is described in the text of this application. The use of the Avery electrode is described in the website of Avery Laboratories, Inc.
Nerves are fragile. Electrode designs are, in large measure, selected to minimize injury to a nerve. Also, it is important that the electrode be designed for facilitating placement of the electrode on the nerve. Most preferably, the electrode is designed to facilitate placement in a less invasive procedure such as a laparoscopic surgical procedure.